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Aditya Narayanan

Bio: Aditya Narayanan is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Geology & Water mass. The author has an hindex of 2, co-authored 3 publications receiving 15 citations.

Papers
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Journal ArticleDOI
TL;DR: Stammerjohn, Sharon; Scambos, Ted A; Adusumilli, Susheel; Barreira, Sandra; Bernhard, Germar H; Bozkurt, Deniz; Bushinsky, Seth M; Clem, Kyle R; Colwell, Steve; De Laat, Jos; du Plessis, Marcel D; Fogt, Ryan L; Foppert, Annie; Fricker, Helen Amanda; Gardner, Alex S; Gille, Sarah T; Gorte, Tessa; Johnson, Bryan; Keen
Abstract: Author(s): Stammerjohn, Sharon; Scambos, Ted A; Adusumilli, Susheel; Barreira, Sandra; Bernhard, Germar H; Bozkurt, Deniz; Bushinsky, Seth M; Clem, Kyle R; Colwell, Steve; Coy, Lawrence; De Laat, Jos; du Plessis, Marcel D; Fogt, Ryan L; Foppert, Annie; Fricker, Helen Amanda; Gardner, Alex S; Gille, Sarah T; Gorte, Tessa; Johnson, Bryan; Keenan, Eric; Kennett, Daemon; Keller, Linda M; Kramarova, Natalya A; Lakkala, Kaisa; Lazzara, Matthew A; Lenaerts, Jan TM; Lieser, Jan L; Li, Zhi; Liu, Hongxing; Long, Craig S; MacFerrin, Michael; Maclennan, Michelle L; Massom, Robert A; Mikolajczyk, David; Montgomery, Lynn; Mote, Thomas L; Nash, Eric R; Newman, Paul A; Petropavlovskikh, Irina; Pitts, Michael; Reid, Phillip; Rintoul, Steven R; Santee, Michelle L; Shadwick, Elizabeth H; Silvano, Alessandro; Stierle, Scott; Strahan, Susan; Sutton, Adrienne J; Swart, Sebastiaan; Tamsitt, Veronica; Tilbrook, Bronte; Wang, Lei; Williams, Nancy L; Yuan, Xiaojun

22 citations

Journal ArticleDOI
TL;DR: In this article, conductivity-temperature-depth data from instrumented seals of the Marine Mammals Exploring Oceans from Pole to Pole program are analyzed to characterize the water masses and the seasonality of the marginal seas.
Abstract: Conductivity-temperature-depth data from instrumented seals of the Marine Mammals Exploring Oceans from Pole to Pole program are analyzed to characterize the water masses and the seasonality of the marginal seas. Bottom temperatures are found to be in a cold regime in Dense Shelf Water (DSW) producing regions, identified in this study as the southern Weddell Sea, Cape Darnley, Prydz Bay, Adélie Coast, and the western Ross Sea. DSW occupies the bottom of the Weddell and Ross Sea continental shelves throughout the year: Production of DSW and vertical overturning occur only during the winter. In the other DSW producing regions, salinity is reduced more markedly during the summer. We identify the Princess Martha Coast, Leopold and Astrid Coast, and the Knox Coast as Low Salinity Shelf Water producing regions, where modified Circumpolar Deep Water (CDW) intrudes onto the continental shelf, reaching areas close to the ice shelves keeping the bottom temperatures in an intermediate regime. The Prince Harald Coast, the Amundsen Sea, and the Bellingshausen Sea experience more intense CDW intrusion, which keeps them in a warm regime year-round. CDW layer thicknesses correlate with the meridional winds over the shelf sea, and with the zonal winds at the slope, while DSW layer thicknesses correlate with the meridional winds over the shelf seas and the curl of the wind stress over the slope. Locations of DSW on the continental shelf coincide with an absence of warmer CDW near the ice shelves.

14 citations

Journal ArticleDOI
08 May 2023
TL;DR: The Southern Ocean Carbon and Heat Impact on Climate (SOCI) program as discussed by the authors was launched to understand and quantify variability of heat and carbon budgets in the Southern Ocean through an investigation of the key physical processes controlling exchanges between the atmosphere, ocean and sea ice using a combination of observational and modelling approaches.
Abstract: The Southern Ocean greatly contributes to the regulation of the global climate by controlling important heat and carbon exchanges between the atmosphere and the ocean. Rates of climate change on decadal timescales are therefore impacted by oceanic processes taking place in the Southern Ocean, yet too little is known about these processes. Limitations come both from the lack of observations in this extreme environment and its inherent sensitivity to intermittent processes at scales that are not well captured in current Earth system models. The Southern Ocean Carbon and Heat Impact on Climate programme was launched to address this knowledge gap, with the overall objective to understand and quantify variability of heat and carbon budgets in the Southern Ocean through an investigation of the key physical processes controlling exchanges between the atmosphere, ocean and sea ice using a combination of observational and modelling approaches. Here, we provide a brief overview of the programme, as well as a summary of some of the scientific progress achieved during its first half. Advances range from new evidence of the importance of specific processes in Southern Ocean ventilation rate (e.g. storm-induced turbulence, sea–ice meltwater fronts, wind-induced gyre circulation, dense shelf water formation and abyssal mixing) to refined descriptions of the physical changes currently ongoing in the Southern Ocean and of their link with global climate. This article is part of a discussion meeting issue ‘Heat and carbon uptake in the Southern Ocean: the state of the art and future priorities’.

4 citations

Journal ArticleDOI
TL;DR: In this paper , the authors used two observational data sets, an eddy-permitting reanalysis product and regional high-resolution simulations, to investigate the interannual variability of the Halo and Taylor Cap for the period 2007-2022.
Abstract: The region of Maud Rise, a seamount in the Weddell Sea, is known for the occurrence of irregular polynya openings during the winter months. Hydrographic observations have shown the presence of a warmer water mass below the mixed layer along the seamount’s flanks, commonly termed the warm-water Halo, surrounding a colder region above the rise, the Taylor Cap. Here we use two observational data sets, an eddy-permitting reanalysis product and regional high-resolution simulations, to investigate the interannual variability of the Halo and Taylor Cap for the period 2007-2022. Observations include novel hydrographic profiles obtained in the Maud Rise area in January 2022, during the first SO-CHIC cruise. It is demonstrated that the temperature of deep waters around Maud Rise exhibits strong interannual variability within the Halo and Taylor Cap, occasionally to such an extent that the two features become indistinguishable. A warming of deep waters by as much as 0.8° C is observed in the Taylor Cap during the years preceding the opening of a polynya in 2016 and 2017, starting in 2011. By analyzing regional simulations, we show that most of the observed variability in the Halo is forced remotely by advection of deep waters from the Weddell Gyre into the region surrounding Maud Rise. Our highest-resolution simulation indicates that mesoscale eddies subsequently transfer the properties of the Halo’s deep waters onto the Taylor Cap. The eddies responsible for such transfer originate in an abrupt retroflection along the inner flank of the Halo.

1 citations

Journal ArticleDOI
TL;DR: In this article , the authors analyzed 15-year observational data and a 5-year Southern Ocean model simulation to quantify the transformation rates of Circumpolar Deep Water (CDW) and the associated heat loss to the surface.
Abstract: We analyze 15-years of observational data and a 5-year Southern Ocean model simulation to quantify the transformation rates of Circumpolar Deep Water (CDW) and the associated heat loss to the surface. This study finds that over the continental shelves of East Antarctica and the Weddell and Ross Seas, surface buoyancy fluxes transform ∼4.4Sv of surface waters into CDW, providing a path for CDW to lose heat to the surface. In addition, ∼6.6Sv of CDW are mixed with surface waters in the Weddell and Ross subpolar gyres. In contrast, enhanced stratification inhibits the outcropping of CDW isopycnals, reducing their transformation rates by a factor of ∼8 over the continental shelf and by a factor of ∼3 over the deeper ocean in the Amundsen and Bellingshausen Seas. The CDW retains its offshore warm properties as it intrudes over the continental shelves, resulting in elevated bottom temperatures there. This analysis demonstrates the importance of processes in subpolar gyres to erode CDW and to facilitate further transformation on the continental shelves, significantly reducing the heat able to access ice shelf fronts. This sheltering effect is strongest in the western Weddell Sea and tends to diminish toward the east, which helps explain the large zonal differences in continental-shelf bottom temperatures and the melt rates of Antarctic ice shelves.

Cited by
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Journal ArticleDOI
TL;DR: The present 2017 Update Report assesses some of the highlights and new insights about the interactive nature of the direct and indirect effects of UV radiation, atmospheric processes, and climate change.
Abstract: This assessment, by the United Nations Environment Programme (UNEP) Environmental Effects Assessment Panel (EEAP), one of three Panels informing the Parties to the Montreal Protocol, provides an update, since our previous extensive assessment (Photochem. Photobiol. Sci., 2019, 18, 595-828), of recent findings of current and projected interactive environmental effects of ultraviolet (UV) radiation, stratospheric ozone, and climate change. These effects include those on human health, air quality, terrestrial and aquatic ecosystems, biogeochemical cycles, and materials used in construction and other services. The present update evaluates further evidence of the consequences of human activity on climate change that are altering the exposure of organisms and ecosystems to UV radiation. This in turn reveals the interactive effects of many climate change factors with UV radiation that have implications for the atmosphere, feedbacks, contaminant fate and transport, organismal responses, and many outdoor materials including plastics, wood, and fabrics. The universal ratification of the Montreal Protocol, signed by 197 countries, has led to the regulation and phase-out of chemicals that deplete the stratospheric ozone layer. Although this treaty has had unprecedented success in protecting the ozone layer, and hence all life on Earth from damaging UV radiation, it is also making a substantial contribution to reducing climate warming because many of the chemicals under this treaty are greenhouse gases.

193 citations

Journal ArticleDOI
TL;DR: In this paper, the authors propose a method to solve the problem of homonymity in the context of homonyms.........................................................................................................Siii Siii S iii Siii.
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188 citations

Journal ArticleDOI
TL;DR: The age and composition of the 14 × 10 6 ǫ km 2 of Antarctica's surface obscured by ice is unknown except for some dates on detrital minerals as mentioned in this paper.

61 citations

BookDOI
01 Jan 2013
TL;DR: In this article, Dieter K. Muller, Linda Lundmark, Raynald H. Lemelin, Anna Thompson-Carr, Margaret Johnston, Emma Stewart, and Jackie Dawson discuss new issues in polar tourism.
Abstract: 1. Introduction: New Issues in Polar Tourism Dieter K. Muller*, Linda Lundmark & Raynald H. Lemelin 2. Looking Back, Venturing Forward: Challenges For Academia, Community and Industry in Polar Tourism Research Patrick T. Maher* 3. What is Arctic Tourism, and Who Should Define It? Arvid Viken* 4. Narrative Frameworks of Consideration: Horizontal and Vertical Approaches to Conceptualising the Sub-Antarctic Eric J. Shelton* 5. Reaching Consensus on Antarctic Tourism Regulation Kees Bastmeijer & Machiel Lamers* 6. The Effectiveness of Environmental Impact Assessments on Visitor Activity in the Ross Sea Region of Antarctica Tanya A. O'Neill*, Megan R. Balks & Jeronimo Lopez-Martinez 7. German Tourism Activities in the Antarctic Area - A Governmental Perspective Manuela Krakau & Heike Herata* 8. The Wild North - Network Cooperation for Sustainable Tourism in a Fragile Marine Environment in the Arctic Region Sandra Magdalena Granquist & Per Ake Nilsson* 9. Tourism Resolving Crisis? Exploring Tourism Development in Iceland in the Wake of Economic Recession Gunnar Thor Johannesson* & Edward H. Huijbens 10. A (Ski) Trip into the Future - Climate Change and Winter Tourism in Polar Sweden in 2040 Patrick Brouder & Linda Lundmark* 11. Conflicting Discourses in Tourism Development - A Case of Kilpisjarvi Village, Finnish Lapland Tuukka Makitie & Anna-Liisa Ylisirnio* 12. Will 'Free Entry into the Forest' Remain? Argumentation Analysis of Finnish and Swedish Discussions on Everyman's Rights Seija Tuulentie* & Outi Rantala 13. National Parks for Tourism Development in Sub-Arctic Areas - Curse or Blessing? The Case of a Proposed National Park in Northern Sweden Dieter K. Muller* 14. Indigenous People: Discussing the Forgotten Dimension of Dark Tourism and Battlefield Tourism Raynald H. Lemelin*, Anna Thompson-Carr, Margaret Johnston, Emma Stewart & Jackie Dawson 15. New Issues in Polar Tourism: Conclusion Linda Lundmark, Raynald H. Lemelin & Dieter K. Muller* Index

41 citations

01 Apr 2019
TL;DR: Near-synchronous interannual fluctuations in salinity observed at five locations on the continental shelf suggest that upstream preconditioning and large-scale forcing influence HSSW salinity, which decreased between 1995 and 2014 and rebounded sharply after 2014.
Abstract: Antarctic Bottom Water (AABW) supplies the lower limb of the global overturning circulation and ventilates the abyssal ocean. In recent decades, AABW has warmed, freshened and reduced in volume. Ross Sea Bottom Water (RSBW), the second largest source of AABW, has experienced the largest freshening. Here we use 23 years of summer measurements to document temporal variability in the salinity of the Ross Sea High Salinity Shelf Water (HSSW), a precursor to RSBW. HSSW salinity decreased between 1995 and 2014, consistent with freshening observed between 1958 and 2008. However, HSSW salinity rebounded sharply after 2014, with values in 2018 similar to those observed in the mid-late 1990s. Near-synchronous interannual fluctuations in salinity observed at five locations on the continental shelf suggest that upstream preconditioning and large-scale forcing influence HSSW salinity. The rate, magnitude and duration of the recent salinity increase are unusual in the context of the (sparse) observational record. Ross Sea Bottom Water, a major source of Antarctic Bottom Water, has experienced significant freshening in recent decades. Here the authors use 23 years of summer measurements to document temporal variability in the salinity of the Ross Sea High Salinity Shelf Water (HSSW) and found that HSSW salinity decreased between 1995 and 2014 and rebounded sharply after 2014.

36 citations